The knock sensors are on the top of the engine. I believe bank 2 is under the intake. I had mine go about 2 years ago, but it was easy (bank 1 is a clean shot so I didn't have to remove the intake). Often it's the wiring/plug and not the actual sensor so inspect it closely.
No pics or diagrams here, but you may find some in the FSM. They're in the valley of the engine on top. $300 is about right, but if that shop thinks an intake is an engine cover, you need to take it to someone who knows WTF they're doing.
I have had so extreme water action in my 4runner and i know from removing the intake that the top of the engine can pool up with some coolant for the bottom of the TB and also in my more recent case water. Though I am not getting a code but it is knocking and sputtering like mad.
If it is not throwing the code, then your knock sensors are probably fine. I really don't understand your question though. Did you drive though a big puddle of water or did you get some bad gas that might have some water in it?
hey guys so I'm having issues again with my knock sensor...had it fixed but I guess my dad's mechanic used a cheap part and it only lasted 1 year.Is there any pics or step by step instructions on how to replace it? I couldn't find any still..
It's not that hard, just follow directions and use a good torque wrench. Here's a good link for the FSM:
http://www.ncttora.com/fsm/1996/SIL/fsm/repair.html